Monoamines in the liquor-contacting nerve cells in the hypothalamus of the lamprey,Lampetra fluviatilis L.

Summary The hypothalamus of adult lampreys (Lampetra fluviatilis L.) was studied by means of light and fluorescence microscopy (Falck's technique). Some single liquorcontacting nerve cells (LCNC) showing a weak green fluorescence were demonstrated in the ventral part of the third ventricle, above the preoptic recess. Caudally numerous fluorescent LCNC occur in the ventral part of the third ventricle, in the infundibular and in the posterior recess. The LCNC are to be observed between or below the ependymal cells lining the ventricular wall. These cells appear to be of the bipolar type. One process with a club-like protrusion is directed into the ventricular lumen, the other one into the opposite direction. Two types of fluorescent LCNC were distinguished: yellowish green cells, containing catecholamines, and yellowish orange cells, containing 5-hydroxytryptamine. Some similarity between the hypothalamic monoaminergic LCNC in lampreys and LCNC of the paraventricular organ of the other vertebrates was found. The localization, structure and monoaminergic nature of the hypothalamic LCNC in lampreys suggest the possibility, that their monoamines are released into the cerebrospinal fluid.I am very obliged to Prof. A.L. Polenov for his continuous help and advice. The skilful technical assistance of Mrs. G.N. Yakshina is gratefully acknowledged.     

Testing for density-dependent effects in sequential censuses

Summary In response to Gaston and Lawton (1987), we evaluated the ability of four statistical procedures to detect density dependence. We used data from the same 16 populations as Gaston and Lawton (1987). In each population, density dependence had been previously established with techniques that use more extensive data. The major axis test (Slade 1977) was rarely (3 populations of 16) capable of detecting density dependence. The autocorrelation test (Bulmer 1975) detected density dependence in 5 of 16 species (14 of 59 tests overall). The randomization procedure (Pollard et al. 1987) detected density dependence in 7 of the 16 data sets (10 of 59 tests overall). The simulation procedure (Vickery and Nudds 1984) detected density dependence in 5 of the 16 data sets (11 of 59 tests overall). We suggest that not all annual census data taken from populations subject to density-dependent effects will actually show evidence of such effects. We conclude that Pollard et al. 's (1987) randomization procedure is the best test for detecting density dependence in sequential census data but it is not as powerful as more elaborate techniques (k-factor analysis, experimentation, etc.), nor is it meant to replace more extensive analyses.     

Distribution of monoamines in the diencephalon and pituitary of the dogfish,Scyliorhinus canicula L.

Summary The distribution of monoamines in the diencephalon and pituitary of the dogfish, Scyliorhinus canicula, has been investigated using the histochemical fluorescence technique of Falck and Hillarp (Falck and Owman, 1965). Terminals of monoamine-containing axons were found in the neurointermediate lobe of the pituitary and the axons were traced, by means of nialamide and L-dopa treatment and lesions, to the nucleus medius hypothalamicus. A separate hypothalamic system converging on the anterior median eminence and the occurrence of aminergic cells in the nuclei lobi inferiores and nucleus medius hypothalamicus were similarly demonstrated. Normal fish show a bilateral uncrossed tegmental tract and two areas of catecholamine-containing neurones in modified ependymal organs. The organum vasculosum hypothalami includes both primary catecholamine and 5-hydroxytryptamine-containing cell types whilst the organum vasculosum praeopticum has only the former type. Both organs contain cells which send club-like processes into the third ventricle. The subcommissural organ does not contain monoamines.The role of hypothalamic catecholamine systems in the regulation of pituitary function is discussed.     

Effect of monoamines on the taste buds in the mouse

Summary Mouse taste buds were investigated following administration of monoamines and their precursors by fluorescence and electron microscopy. The appearance of fluorescent cells within the taste bud and the ultrastructural changes of vesicles in the gustatory cells were due to the treatment of 5-hydroxytryptophan. Small dense-cored vesicles (30–60 nm in diameter) appeared throughout the cytoplasm and accumulated especially at the presynaptic membranes of afferent synapses. Large dense-cored vesicles (80–100 nm) increased twice in number, and electron densities of their cores became more dense as compared with untreated mice. Fluorescent cells appeared in the taste bud of l-DOPA treated mice, whereas no ultrastructural changes were observed. These results suggest that the gustatory cells of the taste bud are capable of taking up and storing monoamines, which might act as neurotransmitters from the gustatory cells to the nerves.     

Histochemical demonstration of acetylcholinesterase in the hypothalamus of the female guinea-pig

Summary The distribution of acetylcholinesterase (AChE) in the hypothalamus of the female guinea pig has been examined histochemically.Activity was found in neurones of the supraoptic, paraventricular and infundibular nuclei; in the lateral hypothalamic area, in cells dorsomedial to the fornix at the level of the paraventricular nucleus and in a large group of cells surrounding the fornix at the level of the in-fundibular nucleus. A small well-stained group of cells, not identified in histological preparations, was present ventral to the paraventricular nucleus. The neuropil stained at the lateral border of the paraventricular nucleus and in the medial mammillary, suprachiasmatic and dorsomedial nuclei. The walls of some blood vessels stained; activity was particularly strong in vessels in the preoptic area and at the base of the median eminence. Nerve fibres on blood vessels ventral to the hypothalamus also stained.The degree of enzyme activity in the cell groups was compared in immature, pregnant, lactating, ovariectomized and hysterectomized animals. The greatest variation occurred in the infundibular nucleus. Hypophysectomy markedly reduced staining in the supraoptic nucleus. The possibility that AChE may be involved in the elaboration or transport of releasing factors is discussed.The authors are indebted to Dr. J. S. Perry for doing the surgery involved in this work. They are also grateful to him and to Dr. R. B. Heap for helpful discussions and to Miss M. Hamon for excellent technical assistance.     

Fluorescent granules in the guinea-pig hypothalamus and their possible relation to neurosecretory substance

Summary Sections of guinea-pig hypothalamus stained by various methods have been studied under bright-field and fluorescence microscopy to determine the characteristics of refractile granules originally observed in fixed tissue stained for cholinesterases but also seen in unfixed, unstained material.When sections of fresh tissue or tissue fixed in formaldehyde: Na₂SO₄ were examined by fluorescence microscopy, the granules emitted with a wave-length between 600 and 620 m. The density and distribution of the granules closely paralleled that of one of the components that stained with the aldehyde-fuchsin and chrome-alum techniques for neurosecretory substance; granules were absent, however, from the area characterized by Herring substance, and from the stained perikarya and beaded axons of the supraoptic and paraventricular nuclei.The granules were most numerous in the median eminence and infundibular nuclei. Their concentration was about average in mature males and in lactating and hypophysectomized females; they were more abundant in late pregnancy and after ovariectomy and were particularly plentiful some weeks after hysterectomy. They were virtually absent from immature males and females.The possible relation of the granules to releasing factors or to vasotocin-like neurosecretory material is discussed.The authors are most grateful to Dr. J. S. Perry who carried out the surgery involved in these experiments. They also wish to express their thanks to Dr. R. B. Heap who, with Dr. Perry, gave invaluable help in planning the experiments and assessing the data; to Mr. S.P. Mann and Dr. D. F. Sharman for advice on the fluorescence technique and to Miss M. Hamon for skilled technical assistance.Publication of the colour pictures was made possible by a generous grant from the Wellcome Foundation; this support is gratefully acknowledged.Thanks are also due to the University of Alberta for a contribution towards the cost of reprints.     

Structural and microspectrofluorometric studies on glial cells from the periventricular and arcuate nuclei of the rat hypothalamus

Summary Fluorescence spectroscopy and electron microscopic techniques have been employed to investigate a class of glial cells that is characterized by the presence in their cytoplasm of large fluorescing inclusions that stain with paraldehyde-fuchsin or chrome-hematoxyline-alum. In the periventricular nucleus the cells have been identified as a population of astrocytes whose inclusions emit an orange-red fluorescence. In the arcuate nucleus there are, in addition to an overwhelming majority of such astrocytes, also some microglial cells with similar characteristics. The ability of the latter to emit any kind of fluorescence has not yet been established. The fluorescence maximum of these astrocytic inclusions was found to be at 640 nm when excited at 405 nm. The data obtained suggest that the fluorescence observed is due to the presence of porphyrins in the astrocytic inclusions. In the majority of our electron microscopic pictures the inclusions lack a bounding membrane. By contrast, neuronal lipofuscin has an outer membrane. In cryostat sections, the lipofuscin emits a yellow fluorescence when excited at 400–410 Onm.     

Effect of superior cervical ganglionectomy on monoamine content in the epithalamic area of the Mongolian gerbil (Meriones unguiculatus): A fluorescence histochemical study

Summary Extirpation of the superior cervical ganglion was performed in a series of Mongolian gerbils. One or two weeks after the ganglionectomy the animals were injected with a monoamine oxidase inhibitor. Subsequently perfusion fixation was performed using the glyoxylic acid-paraformal-dehydemagnesium method (Lorén et al., 1976) for fluorescence histochemical investigation of the monoamines of the pineal complex. In the ganglionectomized animals all of the blue-fluorescent sympathetic fibers in the pineal complex (superficial pineal gland, deep pineal gland and the pineal stalk) completely disappeared. The yellow indolamine fluorescence of the cells in the superficial pineal and the deep pineal, as well as in the pineal stalk, was markedly reduced after ganglionectomy. No change in the morphology or number of sympathetic fibers in the medial habenular nucleus was observed. These results indicate that the presence of sympathetic nerve fibers with perikarya in the superior cervical ganglion is necessary for maintaining a high indolamine content in all three parts of the pineal complex. In addition, the results also indicate that the deep pineal gland is a functional part of the pineal complex. The presence of a functionally active deep pineal, bordering the pineal recess, suggests that part of the pineal hormones might be secreted into the cerebrospinal fluid.This work was supported by the Carlsberg Foundation, the Swedish Natural Science Research Council, grant no. 2126-100, and the Danish Medical Research Council, grant no. 512-7134     

Uptake of DOPA and 5-HTP in pancreatic islets and parafollicular cells studied by combined autoradiographic and fluorescence microscopic techniques

Summary White albino mice were simultaneously injected with ³H-5-HTP and unlabelled DOPA or ³H-DOPA and unlabelled 5-HTP. The distribution patterns of the formed indol- and catecholamines in a) the pancreatic islets and b) the parafollicular cells were then compared by use of a combined autoradiographic-fluorescence microscopic technique.Localization in the same sections of radioactivity and fluorescence representing the respective monoamines corresponded very well for all the time intervals studied both in the pancreatic islets and in the parafollicular cells.In the pancreatic islets the monoamines were localized in all cells shortly after the injection of the precursors. The monoamines then first disappeared from the -cells leaving the -cells with the highest concentration of activity and fluorescence. In the thyroid the activity and fluorescence, localized in the same parafollicular cells, persisted for a longer time than in the islets.The authors wish to express their gratitude to Professor Sven Ullberg, Head of the Department of Toxicology, University of Uppsala, for much valuable advice during this work. The investigation was supported by grants from the Swedish Medical Research Council (No. 12x-713-01), Knut and Alice Wallenbergs Stiftelse and Ragnar and Torsten Söderbergs Stiftelse.     

The innervation of the salivary gland of the moth,Manduca sexta

Summary The salivary glands of the moth, Manduca sexta (Insecta: Sphingidae), are unlike most other salivary glands in that they are innervated from one source only. Vital staining of nerves with methylene-blue reveals numerous fine nerves extending to the glands from the oesophageal nerve, a part of the stomatogastric or visceral nervous system. Light and electron microscopy confirm that only the fluid-secreting cells, confined to a discrete region in these glands, are innervated. Axons with or without glial wrappings are found in intercellular spaces between fluid-secreting cells. Axons lacking a glial sheath contain, after glutaraldehyde-osmium tetroxide fixation, large granular and small agranular vesicles. In nerve endings in glands fixed with permanganate these smaller vesicles are granular, having the electron-dense cores characteristic of monoamine-containing neurons. These nerve endings with synaptoid areas are in close (direct) contact with the fluid-secreting cells.I am grateful to Professor T. Weis-Fogh for accommodation in the department of Zoology and to Dr. Nancy Lane for use of A.R.C. facilities and advice. Thanks are also due to Drs. M. J. Berridge, S.H.P. Maddrell, and W. T. Prince and Mr. R. A. Leslie for helpful discussion. Financial assistance from Clare College, Cambridge is gratefully acknowledged.     

Progesterone reduces the effect of the serotonin 1B/1D receptor antagonist, GR 127935, on lordosis behavior

Ovariectomized rats were hormonally primed with 10 μg estradiol benzoate or with estradiol benzoate plus 500 μg progesterone. Rats received a bilateral infusion with 200 ng of the 5-HT_1B/1D receptor antagonist, N-[4-methoxy-3-(4-methyl-1-piperazinyl)phenyl]-2′-methyl-4′-(5-methyl-1,2,4-oxadiazol-3-yl)-1-1′-biphenyl-4-carboxamide hydrochloride (GR 127935), into the ventromedial nucleus of the hypothalamus (VMN), followed by a 5 min restraint or home cage experience. In estrogen-primed females that had experienced minimal handling between ovariectomy and use in the experiment, infusion with the water vehicle transiently inhibited lordosis behavior, and the 5-HT_1B/1D receptor antagonist amplified this inhibition. There were no effects in rats hormonally primed with estrogen and progesterone. Handling for two days before the experiment reduced the effects of the infusions in estrogen-primed rats. However, when a 5 min restraint experience followed infusion with GR 127935, there was a significant decline in lordosis behavior that persisted for 10 to 15 min after the experience. Regardless of the prior experience or type of infusion, the addition of progesterone to the hormonal priming completely prevented the lordosis inhibition. These findings are consistent with prior evidence that progesterone protects against the inhibitory effects of a 5 min restraint experience on lordosis behavior. Moreover, these are the first experiments to demonstrate an inhibitory effect of a selective 5-HT_1B/1D receptor antagonist in the VMN on lordosis behavior of estrogen primed, but not estrogen and progesterone primed, ovariectomized rats.     

Reverse engineering the lordosis behavior circuit

Reverse engineering takes the facts we know about a device or a process and reasons backwards to infer the principles underlying the structure-function relations. The goal of this review is to apply this approach to a well-studied hormone-controlled behavior, namely the reproductive stance of female rodents, lordosis. We first provide a brief overview on the considerable amount of progress in the analysis of female reproductive behavior. Then, we propose an analysis of the mechanisms of this behavior from a reverse-engineering perspective with the goal of generating novel hypotheses about the properties of the circuitry elements. In particular, the previously proposed neuronal circuit modules, feedback signals, and genomic mechanisms are considered to make predictions in this manner. The lordosis behavior itself appears to proceed ballistically once initiated, but negative and positive hormonal feedback relations are evident in its endocrine controls. Both rapid membrane-initiated and slow genomic hormone effects contribute to the behavior's control. We propose that the value of the reverse-engineering approach is based on its ability to provide testable, mechanistic hypotheses that do not emerge from either traditional evolutionary or simple reductionistic perspectives, and several are proposed in this review. These novel hypotheses may generalize to brain functions beyond female reproductive behavior. In this way, the reverse-engineering perspective can further develop our conceptual frameworks for behavioral and systems neuroscience.     

高灵敏度荧光显微镜量化技术及其在光生物学研究中的应用

介绍一种用像增器接收荧光图像的高灵敏度荧光显微镜,相对于普通荧光显微镜的灵敏度提高了４×１０４倍,并用宽量程微光光亮度计对仪器的微弱成像性能进行了实验标定,得到了图像采集数据和图像发光强度的线性数量关系。高灵敏度荧光显微镜在给出细胞荧光图像的同时,可以给出图像上每一像元的发光强度和细胞平均发光强度,仪器对图像细微变化的判断能力远大于人眼直接观察图像。高灵敏度荧光显微镜可应用于研究细胞中荧光物质在细胞生理过程中的分布变化和发光强度变化。使用此仪器已得到了光敏竹红菌甲素（ＨＡ）在Ｈｅｌａ细胞（人体子宫癌细胞）中的分布图像和更为直观的三维显示图形,以及加入ＨＡ后Ｈｅｌａ细胞受到强先照射后的细胞损伤图像。     

Applied Biology Courses in Secondary Schools

Some comments on existing courses, the accumulated experience of which is in danger of being ignored in the development of new curricula in science.     

Leishmania adleri: in vitro phagocytosis by lizard leukocytes and peritoneal exudate cells

The interaction of iguanid lizard (Dipsosaurus dorsalis) blood cells and promastigote forms of Leishmania adleri Heisch 1954 was observed in vitro by means of wet mount preparations. Some parasites were phagocytized within a short time after their addition to the preparations. Parasites were engaged and engulfed either individually or in masses. Rapid decrease in size of the parasites occurred. The process of phagocytosis of the parasites was found to be very similar to that of mammalian leishmanias in similar preparations with mammalian cells. Cell cultures prepared from peritoneal exudates of lizards (Basiliscus vittatus) were inoculated with L. adleri promastigotes. Resultant intracellular amastigotes were observed up to 36 hr at 25 and 35 C.     

Localization of monoamine-containing neurones in the nervous system ofStrophocheilus oblongus (Gastropoda)

Summary The histochemical fluorescence method of Falck and Hillarp was used to locate monoamine-containing neurones in the nervous system ofStrophocheilus, a Brazilian land snail. Green-fluorescing (catecholamines) cell bodies were found only in cerebral ganglia. Neuropiles of all ganglia contained many green-fluorescing fibers most of which appeared to enter from the periphery. Giant (up to 500 ) non-fluorescing cells were seen in most ganglia of the suboesophageal mass. Green-fluorescing fibers surrounded, and apparently ended on, their axon hillocks and proximal segments of axons. Green-fluorescing sensory cells were seen in the eyeless tentacles. Cells fluorescing yellow (5-hydroxytryptamine) or yellow fading to green on exposure to ultraviolet light were found in cerebral, visceral and right palliai ganglia. Ligature of the cardiac nerve for 24 hrs resulted in an accumulation of yellow or yellow green-fluorescing masses in axons proximal to the constriction. The distribution of monoamine-containing neurones inStrophocheilus is rather similar to that found in other pulmonate molluscs such asHelix.The authors are eager to acknowledge the constant interest of Dr. Sonia Rude while the experiments were taking place. This work was jointly supported by OAS, Capes (Brazil), U. F. R. G. S. (Brazil), and Grant No. NB 00623 (USPHS).     

Fluoreszenzmikroskopische Untersuchungen mit Pseudoisocyaninchlorid am Schlundring einiger stylommatophorer Pulmonaten

Zusammenfassung Durch Anwendung von Pseudoisocyaninchlorid lassen sich im zentralen Nervensystem von stylommatophoren Pulmonaten in allen Schlundringganglien Neurosekretzellen fluoreszenzmikroskopisch nachweisen. In den Cerebralganglien bilden sie mit ihren ausleitenden Axonen das bereits bei einigen Gastropoden bekannte geschlossene neurosekretorische System. In den übrigen Ganglien liegen die neurosekretorischen Zellen einzeln oder in Gruppen zusammen und bilden kein System. Es konnte nachgewiesen werden, daß in Visceral-Parietaganglien der untersuchten Arten die meisten sekretorischen Neurone vorkommen. Die Zahl der neurosekretorischen Zellen in den einzelnen Ganglien ist zumindest für die hier untersuchten Arten wahrscheinlich artspezifisch, ihre topographische Lage in den Ganglien aber bei allen Arten identifizierbar ähnlich. Bei allen untersuchten Pulmonaten fanden sich nur im Procerebrum keine neurosekretorischen Zellen. Die vielfältigen, über die Darstellung der Neurosekretzellen hinaus feststellbaren fluoreszenzmikroskopischen Erscheinungen in den Nerven- und Gliazellen, in der Fasermasse der Ganglien, den Kommissuren und Nerven und im Bindegewebe um die Ganglien, wurden mit Hilfe anderer lichtmikroskopischer Färbungen vergleichend untersucht; die Ergebnisse werden diskutiert.

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Fluorescence-microscopic investigations with pseudoisocyanin on the central nervous system of some stylommatophoran pulmonates

Summary Using fluorescence microscopy with pseudoisocyaninchloride one can demonstrate the well known cells and axons of the neurosecretory system in the cerebral ganglia of some gastropod pulmonates. In the other ganglia of the central nervous system-except procerebrum-single secretory neurones or groups of neurosecretory cells occur. These secretory neurones do not build up a neurosecretory system. The majority of these cells is concentrated in the visceral-parietal ganglia. The specific elements are topographically identifiable relative to each other in the ganglia of each species of pulmonates investigated. Other fluorescence-microscopic investigations of the neurones, glial cells and the neuropil of the ganglia, commissures and nerves and in the connective tissue surrounding the ganglia are described in comparison with other light microscopical findings obtained by staining methods; the results are discussed.